Individuation and study of supported catalytic systems suitable for practically useful C-C cross-coupling reactions performed in batch and/or flow conditions

In the context of organic chemistry, and in particular in the C-C cross-coupling reactions catalyzed by transition metals such as nickel or palladium, the use of green and environmental friendly synthetic methodologies is of growing interest for both Academy and Industry. In this context, the replacement of homogeneous metal catalysts with heterogeneous systems and the replacement of classical batch-type reactors with continuous flow systems is today considered of primary importance. Our investigations demonstrated that under rather simple and convenient conditions (a moderate excess of bases, a moderate amount of organic solvents, or in some cases, in only water or in absence of solvents, under aerobic atmosphere and with very low metals loading (0.10-0.15 mol% of Pd); cheap, simple, practical, easily available and industrially acceptable supported catalysts (“purpose-build” and/or commercial), and continuous-flow packed-bed systems, could be conveniently applied in C-C bond forming reactions of particular interest, such as Mizoroki-Heck alkenylations, Sonogashira-type alkynylations and Suzuki-Miyaura reactions; obtaining very good results. Moreover, we reported the application of these systems in one the firstly synthesis of nataural and analogues bioactive compounds in batch and flow mode using supported catalysts

Individuation and study of supported catalytic systems suitable for practically useful C-C cross-coupling reactions performed in batch and/or flow conditions

In the context of organic chemistry, and in particular in the C-C cross-coupling reactions catalyzed by transition metals such as nickel or palladium, the use of green and environmental friendly synthetic methodologies is of growing interest for both Academy and Industry. In this context, the replacement of homogeneous metal catalysts with heterogeneous systems and the replacement of classical batch-type reactors with continuous flow systems is today considered of primary importance. Our investigations demonstrated that under rather simple and convenient conditions (a moderate excess of bases, a moderate amount of organic solvents, or in some cases, in only water or in absence of solvents, under aerobic atmosphere and with very low metals loading (0.10-0.15 mol% of Pd); cheap, simple, practical, easily available and industrially acceptable supported catalysts (“purpose-build” and/or commercial), and continuous-flow packed-bed systems, could be conveniently applied in C-C bond forming reactions of particular interest, such as Mizoroki-Heck alkenylations, Sonogashira-type alkynylations and Suzuki-Miyaura reactions; obtaining very good results. Moreover, we reported the application of these systems in one the firstly synthesis of nataural and analogues bioactive compounds in batch and flow mode using supported catalysts

Nanoparticolati di Pd supportati preparati via Metal Vapour Synthesis: il primo studio sulle possibilità di impiego in reazioni di Suzuki e tipo-Sonogashira

La catalisi eterogenea sta prendendo sempre più importanze nella ricerca sia accademica che industriale e, la preparazione di catalizzatori supportati "via" MVS si presenta come una tecnica con proprietà e caratteristiche molto interessanti (che si ritrovano sui catalizzatori così preparati), rispetto ai comuni sistemi di preparazione, oltre che ai singoli catalizzatori ottenuti. Pertanto appare molto interessante uno studio sulle possibilità di impiego di questi catalizzatori supportati preparati "via" MVS, non ancora mai stati studiati in reazioni di cross-coupling, e soprattutto nelle reazioni di più grande interesse quali la Suzuki e le alchinilazioni tipo-Sonogashira

Structural characterization of bimetallic Pd-Cu vapor derived catalysts

Pd-Cu bimetallic Solvated Metal Atoms (SMA) were synthesized by metal vapor synthesis technique and supported on PVPy resin. Since the catalytic activity, of the Pd-Cu system turned out to be quite high also compared to the corresponding monometallic system, a structural characterization, using electron microscopy techniques and X-ray Absorption Fine Structure spectroscopy, was performed. HRTEM analysis showed the presence of Pd particles distributed in a narrow range with a mean diameter of about 2.5 nm while the XAFS analysis, confirmed the presence of the Pd nanoparticles but revealed also some alloying with Cu atoms

PALLADIUM NANOPARTICLES SUPPORTED ON MESOPOROUS SILICA: APPLICATIONS IN CONTINUOUS-FLOW MIZOROKI-HECK REACTIONS

Herein we wish to report our recent results in the Mizoroki–Heck alkenylations under batch and continuous-flow ligandless conditions, by using Metal Vapour Synthesis (MVS) derived Pd nanoparticles deposited on mesoporous silica powder (MCM-41)

Polyvinylpyridine-Supported Palladium Nanoparticles: An Efficient Catalyst for Suzuki–Miyaura Coupling Reactions

Palladium nanoparticles (Pd NPs) synthesized by the metal vapor synthesis technique were supported on poly(4-vinylpyridine) 2% cross-linked with divinylbenzene (Pd/PVPy). Transmission electron microscopy revealed the presence of small metal nanoparticles (dm = 2.9 nm) highly dispersed on the PVPy. The Pd/PVPy system showed high catalytic efficiency in Suzuki-Miyaura carbon–carbon coupling reactions of both non-activated and deactivated aromatic iodides and bromides with aryl boronic acids, carried out under an air atmosphere. The high turnover of the catalyst and the ability of the PVPy resin to retain active Pd species are highlighted. By comparing the catalytic performances of Pd/PVPy with those observed by using commercially available Pd-based supported catalysts, the reported system showed higher selectivity and lower Pd leaching

Synthesis of Pterostilbene through supported-catalyst promoted Mizoroki-Heck reaction, and its transposition in continuous flow reactor

\u3cp\u3ePterostilbene, an important polyphenolic compound with interesting biological activities, has been efficiently synthesized through a Mizoroki-Heck reaction catalyzed by commercially available Pd catalysts immobilized onto heterogeneous supports. The synthesis has been transposed in a continuous flow reactor, following two different retrosynthetic approaches. [Figure not available: see fulltext.].\u3c/p\u3

Synthesis of Pterostilbene through supported-catalyst promoted Mizoroki-Heck reaction, and its transposition in continuous flow reactor

\u3cp\u3ePterostilbene, an important polyphenolic compound with interesting biological activities, has been efficiently synthesized through a Mizoroki-Heck reaction catalyzed by commercially available Pd catalysts immobilized onto heterogeneous supports. The synthesis has been transposed in a continuous flow reactor, following two different retrosynthetic approaches. [Figure not available: see fulltext.].\u3c/p\u3

PALLADIUM NANOPARTICLES ON POLYVINYLPYRIDINE SUPPORTS: APPLICATIONS IN CONTINUOUS-FLOW MIZOROKI-HECK REACTIONS

Metal vapor synthesis (MVS) technique provides a valuable synthetic route to obtain supported Pd nanoparticles featuring strictly controlled dimension (< 5 nm). These systems proved highly efficient catalysts in Mizoroki-Heck alkenylations of aryl halides (I, Br) with acrylates, to give the corresponding trans-cinnammates in high yields under batch reaction conditions. Here we wish to report our recent results in continuous-flow Mizoroki-Heck alkenylations using MVS-derived Pd nanoparticles deposited on pyridine-based organic supports, both in the form of powder (PVPy) and as mesoporous organic monolith